U.S. patent application number 12/609016 was filed with the patent office on 2010-06-03 for portable electronic device and method for waking up the same from sleep mode through touch screen.
This patent application is currently assigned to HTC CORPORATION. Invention is credited to Chung-An Chien, Chih-Chang Hsu, Ming-Jer Yang, Shu-Hsiang Yang.
Application Number | 20100134437 12/609016 |
Document ID | / |
Family ID | 41404268 |
Filed Date | 2010-06-03 |
United States Patent
Application |
20100134437 |
Kind Code |
A1 |
Yang; Shu-Hsiang ; et
al. |
June 3, 2010 |
PORTABLE ELECTRONIC DEVICE AND METHOD FOR WAKING UP THE SAME FROM
SLEEP MODE THROUGH TOUCH SCREEN
Abstract
A portable electronic device including a touch screen, a micro
processing unit, a central processor and a display is provided. The
central processor can operate in a normal operation mode or a sleep
mode. The touch screen overlays the display, and includes a first
touch area, a second touch area and at least one electrode. When
the central processor operates in the sleep mode and one of the
first and second touch areas senses a touch, the at least one
electrode generates a touch signal. The micro processing unit
determines whether the touch is sensed by the first or the second
touch area according to the touch signal. If the touch is sensed by
the second touch area, the micro processing unit outputs a wake-up
signal to the central processing unit, so as to switch the central
processor from the sleep mode to the normal operation mode.
Inventors: |
Yang; Shu-Hsiang; (Taoyuan
County, TW) ; Hsu; Chih-Chang; (Taoyuan County,
TW) ; Chien; Chung-An; (Taoyuan County, TW) ;
Yang; Ming-Jer; (Taoyuan County, TW) |
Correspondence
Address: |
JIANQ CHYUN INTELLECTUAL PROPERTY OFFICE
7 FLOOR-1, NO. 100, ROOSEVELT ROAD, SECTION 2
TAIPEI
100
TW
|
Assignee: |
HTC CORPORATION
Taoyuan County
TW
|
Family ID: |
41404268 |
Appl. No.: |
12/609016 |
Filed: |
October 30, 2009 |
Current U.S.
Class: |
345/174 ;
345/169; 455/556.2; 455/566 |
Current CPC
Class: |
G06F 3/0488 20130101;
G06F 1/3203 20130101; G06F 3/04166 20190501; G06F 3/045
20130101 |
Class at
Publication: |
345/174 ;
455/556.2; 345/169; 455/566 |
International
Class: |
G06F 3/045 20060101
G06F003/045; H04M 1/00 20060101 H04M001/00; G06F 3/02 20060101
G06F003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 28, 2008 |
TW |
97146568 |
Claims
1. A portable electronic device, comprising: a central processor,
capable of operating in a sleep mode and a normal operation mode; a
display, having a display area for displaying information; a touch
screen, overlaid on the display and having a first touch area
overlaid on the display area of the display, a second touch area
extending to outside of the display area, and at least one
electrode, wherein when the central processor operates in the sleep
mode and one of the first and the second touch areas senses a
touch, the at least one electrode generates a touch signal; and a
micro processing unit, electrically connected to the at least one
electrode, for determining whether the touch is sensed by the first
or the second touch area according to the touch signal, wherein
when the touch is sensed by the second touch area, the micro
processing unit outputs a wake-up signal to the central processor,
so as to switch the central processor from the sleep mode to the
normal operation mode.
2. The portable electronic device as claimed in claim 1, further
comprising: a touch screen controller, electrically connected
between the touch screen and the central processor, wherein when
the central processor operates in the normal operation mode, the
touch screen controller transmits a plurality of scanning voltages
to the touch screen to detect and obtain a coordinate value of a
touch point and sends a read signal to make the central processor
read the coordinate value of the touch point.
3. The portable electronic device as claimed in claim 2, wherein
the micro processing unit outputs the wake-up signal to the central
processor through an inter-integrated circuit (I2C) bus.
4. The portable electronic device as claimed in claim 1, wherein
the micro processing unit comprises: an analog to digital
converter, electrically connected to the at least one electrode,
for converting the touch signal into a touch information, wherein
the micro processing unit determines whether the touch is sensed by
the first or the second touch area according to the touch
information.
5. The portable electronic device as claimed in claim 1, wherein
the touch screen is a resistive touch screen.
6. The portable electronic device as claimed in claim 1, wherein
the at least one electrode comprises a first electrode, a second
electrode, a third electrode and a fourth electrode, and the touch
screen comprises: a transparent thin film, wherein the first and
the second electrodes are disposed at two sides of the transparent
thin film along a first direction; a transparent glass, wherein the
third and the fourth electrodes are disposed at two sides of the
transparent glass along a second direction; a plurality of spacers,
disposed between the transparent thin film and the transparent
glass; and a frame, disposed around the transparent glass, for
fixing the transparent thin film on the transparent glass.
7. The portable electronic device as claimed in claim 6, wherein
the first direction is substantially perpendicular to the second
direction.
8. The portable electronic device as claimed in claim 6, wherein
when the central processor operates in the sleep mode, the touch
screen controller transmits a pull-up voltage conducted between the
second and the third electrodes, and the micro processing unit is
electrically connected to the first or the second electrode.
9. The portable electronic device as claimed in claim 8, wherein
the touch screen further comprises a plurality of touch keys
disposed along the second direction in parallel.
10. The portable electronic device as claimed in claim 1, further
comprising: a housing, for containing the micro processing unit,
the central processor and the touch screen controller, wherein the
touch screen is disposed on a surface of the housing.
11. The portable electronic device as claimed in claim 1, which is
a PDA phone, a smart phone, a satellite navigator or a PDA.
12. A method for waking up a portable electronic device from a
sleep mode through a touch screen, the portable electronic device
having a central processor, a touch screen and a micro processing
unit, and the touch screen having a first touch area and a second
touch area, the method comprising: sensing a touch by one of the
first and the second touch areas; generating a touch signal when
the touch is sensed; according to the touch signal, determining, by
the micro processing unit, whether the touch is sensed by the first
or the second touch area and outputting a wake-up signal if the
touch is sensed by the second touch area; and switching the central
processor from the sleep mode to a normal operation mode according
to the wake-up signal.
13. The method as claimed in claim 12, further comprising:
transmitting a plurality of scanning voltages to the touch screen
to detect and obtain a coordinate value of a touch point in the
normal operation mode, and sending a read signal to read the
coordinate value of the touch point.
14. The method as claimed in claim 12, wherein the step of
outputting the wake-up signal according to the touch signal
comprises: converting the touch signal into a touch information;
and determining whether the touch is sensed by the first or the
second touch area according to the touch information.
15. The method as claimed in claim 12, wherein the touch screen is
a resistive touch screen.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan
application serial No. 97146568, filed on Nov. 28, 2008. The
entirety of the above-mentioned patent application is hereby
incorporated by reference herein and made a part of this
specification.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a portable electronic
device and a method for waking up the same from a sleep mode. More
particularly, the present invention relates to a portable
electronic device and a method for waking up the same from a sleep
mode through a touch screen.
[0004] 2. Description of Related Art
[0005] With a quick development of technology, most of portable
electronic devices apply a touch screen to improve an operation
convenience thereof. Presently, the touch screens are approximately
grouped into resistive touch screens, capacitive touch screens,
infrared touch screens and ultrasound touch screens, etc. Since the
resistive touch screen has a low cost, and a technique development
thereof is relatively mature, it becomes a mainstream in
development of the market.
[0006] FIG. 1 is a block diagram illustrating a conventional
electronic device having a touch screen. Referring to FIG. 1, the
electronic device 100 applies a touch screen controller 120 to
control a resistive touch screen 110. In a normal operation mode,
the touch screen controller 120 may send a plurality of scanning
voltages to the resistive touch screen 110 to detect a coordinate
value of a touch point. Moreover, a central processor 130 receives
a read signal IN11 from the touch screen controller 120, and reads
the coordinate value VL1 stored in the touch screen controller 120
to perform a corresponding operation.
[0007] On the other hand, when the central processor 130 enters a
sleep mode, it can only be waked up and switched to the normal
operation mode in response to an enabling signal IN12 sent from a
physical key 140. The central processor 130 may send an enabling
signal IN13 to the touch screen controller 120 for waiting to read
the coordinate value VL1 only when the central processor 130 is in
the normal operation mode. In other words, in the sleep mode, a
user has to first press the physical key 140 to wake up the central
processor 130, and then the central processor 130 can read the
coordinate value VL1 stored in the touch screen controller 120 to
perform the corresponding operation.
[0008] It should be noted that in recent years, various electronic
products have a general development trend of easy operation,
small-size and large screen size, and especially for the portable
electronic device, a requirement for a volume and the screen size
thereof is more strict. Therefore, in a plenty of the electronic
products, the touch screen and a liquid crystal panel are
integrated to save a space originally used for containing a
keyboard or the physical key, so as to enlarge a configurable area
of the screen. However, regarding a conventional electronic device,
while the screen size thereof is expended, a hardware space of the
physical key has to be maintained, so as to facilitate waking up
the central processor. In this case, not only the features of the
small size and the large screen size of the electronic device are
hard to be achieved, but also a usage complexity of the touch
screen is increased.
SUMMARY OF THE INVENTION
[0009] The present invention is directed to a portable electronic
device, in which a central processor in a sleep mode can be
directly waked up by operating a touch screen.
[0010] The present invention is directed to a method for waking up
a portable electronic device from a sleep mode through a touch
screen, by which a central processor in the sleep mode can be waked
up through the touch screen in a most power-saving approach.
[0011] The present invention provides a portable electronic device
including a touch screen, a micro processing unit, a central
processor and a display. The central processor can operate in a
normal operation mode or a sleep mode. The display has a display
area for displaying information. The touch screen overlays the
display, and includes a first touch area overlaid on the display
area of the display, a second touch area extending to outside of
the display area, and at least one electrode. When the central
processor is in the sleep mode and one of the first and the second
touch areas senses a touch, the at least one electrode generates a
touch signal. The micro processing unit is electrically connected
to the at least one electrode and determines whether the touch is
sensed by the first or the second touch area according to the touch
signal. If the touch is sensed by the second touch area, the micro
processing unit outputs a wake-up signal to the central processor,
so as to switch the central processor from the sleep mode to the
normal operation mode.
[0012] In an embodiment of the present invention, the portable
electronic device further includes a touch screen controller
electrically connected between the touch screen and the central
processor. When the central processor operates in the normal
operation mode, the touch screen controller transmits a plurality
of scanning voltages to the touch screen to detect and obtain a
coordinate value of a touch point, and sends a read signal to the
central processor to make the central processor read the coordinate
value of the touch point.
[0013] In an embodiment of the present invention, the at least one
electrode includes a first electrode, a second electrode, a third
electrode and a fourth electrode, and the touch screen includes a
transparent thin film, a transparent glass, a plurality of spacers
and a frame. The first and the second electrodes are disposed at
two sides of the transparent thin film along a first direction. The
third and the fourth electrodes are disposed at two sides of the
transparent glass along a second direction. The frame is used for
fixing the transparent thin film on the transparent glass.
Moreover, the micro processing unit is electrically connected to
the first or the second electrode, and when the central processor
is in the sleep mode, the touch screen controller transmits a
pull-up voltage conducted between the second and the third
electrodes.
[0014] The present invention provides a method for waking up a
portable electronic device from a sleep mode through a touch
screen. The portable electronic device includes a central
processor, a touch screen and a micro processing unit. The touch
screen has a first touch area and a second touch area, and the
method includes following steps. First, one of the first and the
second touch areas senses a touch to generate a touch signal. Next,
the micro processing unit determines whether the touch is sensed by
the first or the second touch area according to the touch signal,
and if the touch is sensed by the second touch area, the micro
processing unit outputs a wake-up signal. Finally, the central
processor is switched from the sleep mode to a normal operation
mode according to the wake-up signal.
[0015] In the present invention, the micro processing unit reads a
signal of a part of the electrodes of the touch screen, so that the
micro processing unit can wake up the central processor from the
sleep mode according to the signal received from the touch
screen.
[0016] In order to make the aforementioned and other objects,
features and advantages of the present invention comprehensible, a
preferred embodiment accompanied with figures is described in
detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
[0018] FIG. 1 is a block diagram illustrating a conventional
electronic device having a touch screen.
[0019] FIG. 2 is block diagram illustrating a portable electronic
device according to an embodiment of the present invention.
[0020] FIG. 3 is a schematic diagram illustrating an appearance of
a portable electronic device of FIG. 2.
[0021] FIG. 4 is cross-sectional view of a resistive touch
screen.
[0022] FIG. 5 is an explosion diagram of a resistive touch
screen.
[0023] FIG. 6 is a structural diagram of a pressed resistive touch
screen.
[0024] FIG. 7 is an equivalent circuit diagram of a pressed
resistive touch screen.
[0025] FIG. 8A and FIG. 8B are equivalent circuit diagrams of a
resistive touch screen exerted with scanning voltages.
[0026] FIG. 9 is an equivalent circuit diagram of a resistive touch
screen exerted with a pull-up voltage.
[0027] FIG. 10 is a flowchart illustrating a method for waking up a
portable electronic device from a sleep mode through a touch screen
according to an embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0028] FIG. 2 is block diagram illustrating a portable electronic
device according to an embodiment of the present invention.
Referring to FIG. 2, the portable electronic device 200 includes a
touch screen 210, a touch screen controller 220, a central
processor 230, a micro processing unit 240 and a display 250. The
touch screen 210 and the display 250 form a touch display panel
260, and the touch screen 210 includes a plurality of electrodes
(not shown). The micro processing unit 240 includes an analog to
digital converter 241.
[0029] Regarding the whole structure, the touch screen controller
220 is electrically connected to the electrodes. Moreover, the
micro processing unit 240 is electrically connected to a part of
the electrodes through the analog to digital converter 241, and the
control processor 230 is electrically connected to the touch screen
controller 220 and the micro processing unit 240. Moreover, the
portable electronic device 200 of the present embodiment is, for
example, a personal digital assistant (PDA) phone, a smart phone, a
satellite navigator or a PDA, etc.
[0030] In a whole operation, when the central process 230 is
switched to and operates in a normal operation mode, the touch
screen controller 220 transmits a plurality of scanning voltages to
the touch screen 210 to detect and obtain a coordinate value VL2 of
a touch point when the touch screen 210 senses a touch. On the
other hand, the touch screen controller 220 can transmits a read
signal IN21 to the central processor 230 to make the central
processor 230 read the coordinate value VL2 of the touch point.
[0031] On the other hand, when the central processor 230 is
switched to and operates in a sleep mode, the touch screen
controller 220 stops transmitting the scanning voltages. Moreover,
the central processor 230 now can transmit an acquisition signal
IN22 to the micro processing unit 240. When the micro processing
unit 240 receives the acquisition signal IN22, the analog to
digital converter 240 converts a signal received from a part of the
electrodes into a touch information IFM, and the micro processing
unit 240 determines whether or not to output a wake-up signal S22
to the central processor 230 according to the touch information
IFM.
[0032] Accordingly, when the central processor 230 in the sleep
mode receives the wake-up signal S22, it can be waked up and
switched to the normal operation mode. Comparatively, the central
processor 230 in the normal operation mode can send an enabling
signal IN23 to the touch screen controller 220, so as to read the
coordinate value VL2 of the touch point on the touch screen 210
through the touch screen controller 220.
[0033] In other words, a user can directly wake up the central
processor 230 of the portable electronic device 200 by touching a
specific region of the touch screen 210. Therefore, the portable
electronic device 200 can be normally operated without applying a
physical key, so that a screen size of the portable electronic
device 200 can be effectively expended, which avails
miniaturization of the portable electronic device 200.
[0034] For example, FIG. 3 is a schematic diagram illustrating an
appearance of the portable electronic device of FIG. 2. Referring
to FIG. 3, the portable electronic device 200 further includes a
housing 310 and a plurality of touch keys 321, 322, 323 and 324.
The housing 310 is used for containing the micro processing unit
240, the central processor 230 and the touch screen controller 220.
The touch screen 210 is disposed on a surface of the housing 310
and is overlaid on the display 250. In the present embodiment, the
touch screen 210 has a first touch area A31 and a second touch area
A32, and the display 250 has a display area A33 used for displaying
information. The first touch area A31 of the touch screen 210 is
overlaid on the display area A33 of the display 250, and the second
touch area A32 of the touch screen 210 extends to outside of the
display area A33. Moreover, the touch keys 321-324 are arranged on
the second touch area A32 of the touch screen 210.
[0035] Referring to FIG. 2 and FIG. 3, in the sleep mode, the touch
screen controller 220 does not transmit the scanning voltages to
the touch screen 210, though there still has a pull-up resistance
(which is described later with reference of FIG. 9) connected to a
part of the electrodes on the touch screen 210. Therefore, when the
first touch area A31 or the second touch area A32 senses a touch,
such part of the electrodes can still generate a corresponding
signal. In the present embodiment, whether the central processor
230 is waked up is determined according to the corresponding signal
(i.e. a touch signal S21) generated by the electrodes. In other
words, when the first touch area A31 or the second touch area A32
senses a touch, a part of the electrodes generates the touch signal
S21. The analog to digital converter 241 of the micro processing
unit 240 converts the touch signal S21 into the touch information
IFM, and the micro processing unit 240 can determine whether the
touch is sensed by the first touch area A31 or the second touch
area A32 according to the touch information IFM. If the micro
processing unit 240 determines that the touch is sensed by the
second touch area A32, it represents that one of the touch keys
321-324 is pressed, and therefore the micro processing unit 240
outputs the wake-up signal S22 to the central processor 230.
[0036] It should be noted that a division of the first touch area
A31 and the second touch area A32, i.e. the arrangement position of
the touch keys 321-324, correspondingly relates to a judgement
mechanism of the micro processing unit 240. In the follow content,
a resistive touch screen is taken as an example for
description.
[0037] FIG. 4 is cross-sectional view of a resistive touch screen,
and FIG. 5 is an explosion diagram of a resistive touch screen.
Referring to FIG. 4, the resistive touch screen 400 includes a
transparent thin film 410, a frame 420, a transparent glass 430 and
a plurality of spacers 440. The spacers 440 are disposed between
the transparent thin film 410 and the transparent glass 430 to form
a gap between the transparent thin film 410 and the transparent
glass 430. Moreover, the frame 420 is disposed around the
transparent glass 430 to fix the transparent thin film 410 on the
transparent glass 430.
[0038] Moreover, as shown in FIG. 5, the resistive touch screen 400
applies a four-wire-sensing technique, so that electrodes EX+ and
EX- are disposed at two sides of the transparent thin film 410, and
electrodes EY+ and EY- are disposed at two sides of the transparent
glass 430. The electrodes EX+ and EX- are disposed on the
transparent thin film 410 along a Y-axis direction, and the
electrodes EY+ and EY- are disposed on the transparent glass 430
along an X-axis direction, wherein the X-axis direction is
substantially perpendicular to the Y-axis direction.
[0039] Generally, when no press is exerted to the resistive touch
screen 400, the spacers 410 space the transparent thin film 410 and
the transparent glass 430 to isolate the upper and lower conductive
layers of the resistive touch screen 400. However, when a finger or
a stylus presses the transparent thin film 410, the transparent
thin film 410 is conducted to the transparent glass 430 to generate
a potential difference.
[0040] For example, FIG. 6 is a structural diagram of a pressed
resistive touch screen, and FIG. 7 is an equivalent circuit diagram
of the pressed resistive touch screen. As shown in FIG. 6, when a
touch point P of the resistive touch screen 400 is pressed, a press
resistance R.sub.Z is generated between the transparent thin film
410 and the transparent glass 430, and the transparent thin film
410 and the transparent glass 430 are mutually conducted. Moreover,
the resistive touch screen 400 can respectively generate
resistances R.sub.X+, R.sub.X-, R.sub.Y+ and R.sub.y- along the
X-axis direction and the Y-axis direction based on the touch point
P. Therefore, the equivalent circuit of the resistive touch screen
400 is now as that shown in FIG. 7, wherein a voltage difference
between voltages V.sub.X and V.sub.Y is the potential difference
generated when the transparent thin film 410 and the transparent
glass 430 are mutually conducted.
[0041] In the following content, an operation mechanism of the
touch screen controller 220 under the normal operation mode, and
how the micro processing unit 240 judges the signal sent from the
resistive touch screen 400 to wake up the central processor 230
from the sleep mode to the normal operation mode are respectively
described according to a circuit characteristic of the resistive
touch screen shown in FIG. 7.
[0042] In allusion to the four-wire-sensing technique, the position
of the touch point P is determined according to a method that two
points can determine one position. Therefore, when the touch screen
controller 220 is switched to the normal operation mode, the
voltages V.sub.X and V.sub.Y can be detected by exerting the
scanning voltages. Comparatively, after the touch screen controller
220 obtains the voltages V.sub.X and V.sub.Y, the voltages V.sub.X
and V.sub.Y are calculated and converted into the coordinate value
of the touch point P by the touch screen controller 220.
[0043] For example, FIG. 8A and FIG. 8B are equivalent circuit
diagrams of a resistive touch screen applied with the scanning
voltages. Under the normal operation mode, first, as shown in FIG.
8A, the touch screen controller 220 applies a scanning voltage
V.sub.S1 between the electrodes EX+ and EX-, and detects the
voltage V.sub.Y through the electrode EY+. Then, as shown in FIG.
8B, the touch screen controller 220 applies a scanning voltage
V.sub.S2 between the electrodes EY+ and EY-, and detects the
voltage V.sub.X through the electrode EX+. It should be noted that
the touch screen controller 220 can swiftly apply the scanning
voltages V.sub.S1 and V.sub.S2 alternately, so as to immediately
convert the detected voltages V.sub.X and V.sub.Y into the
coordinate value of the touch point P.
[0044] On the other hand, when the touch screen controller 220 is
switched to the sleep mode, the touch screen controller 220 stops
transmitting the scanning voltages V.sub.S1 and V.sub.S2. Moreover,
as shown in FIG. 9, the touch screen controller 220 can transmit a
pull-up voltage V.sub.PU conducted between the electrode EX+ and
the electrode EY-. The touch screen controller 220 transmits the
pull-up voltage V.sub.PU to the electrode EX+ through a resistance
R.sub.PU. It should be noted that if now the micro processing unit
240 is electrically connected to the electrode EX-, a voltage
V.sub.EX-, derived by the following equation (1), can be detected
and obtained.
V EX - = R Z + R Y - R PU + R X + + R Z + R Y - .times. V PU ( 1 )
##EQU00001##
[0045] Referring to FIG. 3 and FIG. 9, since the touch keys 321-324
are arranged in parallel along the X-axis direction, and are closed
to the electrode EY- of the touch screen 400, when one of the touch
keys 321-324 is pressed, the resistance R.sub.Y- generated along
the Y-axis direction is smaller than that generated when a region
outside the touch keys 321-324 is pressed, and the greater a
pressing force is, the smaller the R.sub.Z is. Accordingly, the
micro processing unit 240 can set a corresponding predetermined
voltage information in internal thereof according to the equation
(1) and variations of the resistances R.sub.Z and R.sub.Y-. By such
means, when the analog to digital converter 241 converts the
voltage V.sub.EX- (i.e. the touch signal S21) generated by the
second touch area A32 into the touch information IFM according to
the acquisition signal IN22, the micro processing unit 240 can
compare the touch information IFM to the predetermined voltage
information, and determine whether or not to output the wake-up
signal S22 according to a comparison result thereof For example, if
the comparison result shows that the voltage V.sub.EX-
corresponding to the touch information IFM is determined to be less
than, greater than or equal to a predetermined voltage, the micro
processing unit 240 outputs the wake-up signal S22. Conversely, the
micro processing unit 240 does not output the wake-up signal
S22.
[0046] On the other hand, if the micro processing unit 240 is
electrically connected to the electrode EX+, the voltage V.sub.EX+,
derived by the following equation (2), can be detected and
obtained:
V EX + = R X + + R Z + R Y - R PU + R X + + R Z + R Y - .times. V
PU ( 2 ) ##EQU00002##
[0047] Now, as that shown in FIG. 9, limited to the arrangement
position of the touch keys 321-324, the resistance R.sub.Y- is
smaller than a resistance generated when a region outside the touch
keys 321-324 is pressed, and the greater the pressing force is, the
smaller the R.sub.Z is. Therefore, the micro processing unit 240
can set a corresponding predetermined voltage information in
internal thereof according to the equation (2) and variations of
the resistances R.sub.Z, R.sub.X+ and R.sub.Y-.
[0048] In other words, the predetermined voltage information set by
the micro processing unit 240 can be varied according to different
electrodes read by the micro processing unit 240 and different
arrangement position of the touch keys. Therefore, those skilled in
the art can correspondingly change the predetermined voltage
information of the micro processing unit in case that the electrode
read by the micro processing unit or the arrangement position of
the touch keys is changed, and therefore the micro processing unit
can determine whether or not to output the wake-up signal according
to the signal sent from the touch screen.
[0049] According to another aspect, FIG. 10 is a flowchart
illustrating a method for waking up a portable electronic device
from a sleep mode through a touch screen according to an embodiment
of the present invention, wherein the portable electronic device
has a central processor, a touch screen and a micro processing
unit, and the touch screen has a first touch area and a second
touch area. Referring to FIG. 10, in step S110, the first and the
second touch areas sense a touch. Next, in step S120, when the
touch is sensed, a touch signal is correspondingly generated, and
in step 5130, the micro processing unit determines whether the
touch is sensed by the first or the second touch area according to
the touch signal, and if the touch is sensed by the second touch
area, the micro processing unit outputs a wake-up signal. By such
means, in step 5140, the central processor is switched from a sleep
mode to a normal operation mode according to the wake-up signal.
Moreover, in step S150, in the normal operation mode, a plurality
of the scanning voltages is transmitted to the touch screen to
detect and obtain a coordinate value of a touch point, and a read
signal is sent to read the coordinate value of the touch point.
Detailed detection method of the present embodiment has been
described in the aforementioned embodiments, and therefore detailed
description thereof is not repeated.
[0050] In summary, in the present invention, the micro processing
unit reads the signal of a part of the electrodes of the touch
screen, so that the micro processing unit can wake up the central
processor in the sleep mode according to the signal received from
the touch screen. By such means, the touch screen of the portable
electronic device can normally operate without applying the
physical key, so that the screen size of the portable electronic
device can be effectively expended, which avails miniaturization of
the portable electronic device. On the other hand, since the user
can directly wake up the central processor through the touch
screen, the usage complexity of the touch screen can be
simplified.
[0051] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
present invention cover modifications and variations of this
invention provided they fall within the scope of the following
claims and their equivalents.
* * * * *